bypasskondensator

A bypass capacitor is a capacitor used to shunt, or bypass, unwanted signals or noise from one point to another in an electronic circuit. These capacitors are typically placed in parallel with a component or signal path that is susceptible to interference or is generating noise. Their primary function is to provide a low-impedance path for high-frequency signals, effectively diverting them away from sensitive areas.

In digital circuits, bypass capacitors are crucial for filtering out high-frequency noise generated by switching transistors and other active components. This noise can propagate through the power supply rails and disrupt the operation of other parts of the circuit. By placing a bypass capacitor close to the power pins of an integrated circuit, the noise generated by that chip is shunted to ground, preventing it from affecting other components.

Similarly, in analog circuits, bypass capacitors can be used to filter out unwanted AC signals from DC power supplies, ensuring a clean and stable voltage for sensitive analog components. They can also be employed to prevent signal coupling between different stages of an amplifier or other analog systems. The effectiveness of a bypass capacitor depends on its capacitance value, its placement within the circuit, and its equivalent series resistance (ESR) and equivalent series inductance (ESL), which become important at very high frequencies. Typically, smaller ceramic capacitors with low ESR and ESL are preferred for bypass applications.